In the manufacture of containers, various anomalies can occur that affect the commercial acceptability of the containers. Such anomalies are known as “commercial variations” and can involve one or more attributes of the container. For example, commercial variations can include dimensional characteristics of the container at an open mouth of the container. Thus, it is often times useful to provide inspection equipment capable of inspecting the containers for commercial variations. The term “inspection” is used in its broadest sense to encompass any optical, electro-optical, mechanical or electrical observation or engagement with a container to measure or determine a container characteristic, including but not necessarily limited to commercial variations. U.S. patents that illustrate inspection processes of this type for glass containers include U.S. Pat. Nos. 5,461,228 and 6,175,107.
A general object of the present disclosure, in accordance with one aspect of the disclosure, is to provide a more reliable optical plug gage (OPG) apparatus and method for more accurately gaging a size of a container mouth bore.
The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other.
In accordance with an aspect of the disclosure, there is provided a method of inspecting a container having a base and a mouth. Light is directed through the container base into the container, and out of the container through the container mouth, using at least one light source disposed beneath the container base. A plurality of images of the container mouth is obtained from the light directed through the container mouth, and minimum bore diameters of the container mouth are calculated from the plurality of images. An overall lowest minimum bore diameter (OLMBD) of the minimum bore diameters is identified, and an effective minimum bore diameter of the container mouth is determined to be a value other than the OLMBD.
In accordance with another aspect of the disclosure, there is provided an apparatus for inspecting a container having a base and a mouth. At least one light source is disposed beneath the container base, wherein the light source directs light through the container base into the container, and out of the container through the container mouth. A light sensor is disposed with respect to the light source and the container to sense light transmitted through the container mouth. A processor acquires a plurality of images of the container mouth from the light sensor, calculates minimum bore diameters of the container mouth from the plurality of images, identifies an overall lowest minimum bore diameter (OLMBD) of the minimum bore diameters, and determines an effective minimum bore diameter of the container mouth to be a value other than the OLMBD.